Cologne, Dresden and/or Heidelberg??

Cologne (Köln) wouldn't be very high on my priorities list. Look at Erfurt. Nice, non-touristy city, halfway between Dresden and Heidelberg, and a good base for places like Weimar and Gotha.
While in Dresden, have a day-trip to Leipzig. I found it an amazingly attractive city. Depending on the season, have a day-trip from Heidelberg to nearby Schwetzingen with its palace and gardens. (There is a half-hourly bus #717 from Heidelberg Hbf.)

If you are counting nights in each place... 25 - 14 (Munich, Berlin) - 5 (Paris) = 6 nights remaining.

Haven't been to Dresden since shortly after the Wall came down. The other two places are deficient in one or more of the elements you are looking for.

" We love architecture, museums, green spaces and wandering around new cities."
Between H'berg and Cologne lies Mainz, on the Rhine just west of FRA airport. It covers your interests relatively well and is close enough to Cologne and H'berg that you could day trip to one or both.

Mainz' tangle of pedestrians-only streets (in pink)
Mainz' city park
Market Square
Market Square cafes
Playful fountains
Mainz' old town
Museums, cathedrals and other sights

Note also that just northwest of Mainz is the UNESCO World Heritage Middle Rhine Valley. A direct train ride of roughly 20 minutes gets you to Bingen, where the castles and the scenery begin. Just beyond Bingen lie Bacharach, Oberwesel, and other old-world, half-timbered towns.

Scene near Bingen
River cruise
Bacharach
Oberwesel (good place to stretch your legs)
St. Goar and Rheinfels Castle
Gedoen's Corner, top of chair lift in Boppard
Braubach

Sounds like you would be going from Cologne/Heidelberg/Dresden just before going to Paris. What form of transportation would you use? It's a long trip by train from Dresden to Paris and I can't see any convenient flights. Either Köln or Heidelberg would be faster by train when you consider all of the additional times (getting to an airport, check in, security, waiting to board, etc) involved with flying. I've been to all three, and I don't really think there is enough in any of them for much more than a day, let alone 3 or 4, but I only spent a few hours in the middle of the day in Köln, so I didn't really research what else there is to see there. Of course, I don't particularly like large cities, so if I were doing it, I would head up the Rhein to the St. Goar area.

On the other hand, if you want to put the stop in between Berlin and Munich, Dresden would be the logical choice, geographically.

I've been to all three, and I don't really think there is enough in
any of them for much more than a day, let alone 3 or 4,

Must sees in and around Dresden
Museums:
Old Masters
Green Vault(s)
Armory
Military Museum
Porcelain Collection
Cabinet of Mathematical and Physical Instruments

Buildings and structures:
Zwinger
Frauenkirche
Semper Opera
Brühls Terrace
Great Garden
Pillnitz castle
Moritzburg castle

Unique Transport:
Funicular Railway
Suspension Railway
Paddle steamers fleet
Radebeul steam train

Day trips:
Saxon Switzerland
Königstein fortress
Meissen
Freiberg
Bautzen
Görlitz
Seiffen (Christmas village)

... and much more

Thank you all for the information. It is very helpful! I would like a bit more about why Dresden is fantastic, if you care to address that. Susan

Gee, since Martin gave you hot-links for the Dresden attractions, I think you can determine for yourself why it's such a great destination. I certainly liked it better than Munich, where we spent three nights. Also, Dresden is in the former "Ost", so it has awakening and redeveloping areas in a way that Berlin has already passed into vulgar gentrificaton. It is near some great excursions or overnights, like Erfurt and Weimar (and Buchenwald.) While Leipzig is on the way, Dresden is even better (unless you are dedicated to the Bach family ... )

Only drawback, same as Berlin's ... .... all those plaques that say, "Wiederaufbauen 19xx".

Hi,

Of your 3 choices, I would recommend Dresden as one of them. As pointed out above, you'll be within day trip distance to Weimar to see the town of Goethe and Schiller, plus Naumburg. Both places are paramount in German cultural history.

In Weimar if you are interested in visiting the Buchenwald concentration camp, that can be easily done by taking the bus from the Goetheplatz, ca 30 min walk from the train station. Signs point the way. Weimar is a lovely, relaxing town, has a different feel to it compared to towns of like size in western Germany.

Thank you, everyone. I am already using your information in my trip planning. Susan

I went to Dresden in 2006 for three days to see the Fraunkirsche grand opening and spent time at the museums,went back the next year and went to the New Green Vault which is a collection of Agustus the Strong,it was one of the most impressive museums that I have visited,Moritzburg is Agustus Hunting Lodge surrounded by a moat,there is so much to see in Dresden it is definitely worth 3-4 days.We took the train to Saxon Switzerland and the boat ride back and you can see the Fraunkirchefrom about a mile out,thereis also Pfunds Dairy store,very unique.The museums are all in the same area as well as the opera house.If you have a car go to Gorlitz and Bautzen near the Polish border,these people are the Zorbs in Bautzen.The area is one of my favorites in Europe.
Mike